Device Overview
MCF51CN128 Reference Manual, Rev. 6
Freescale Semiconductor
1-7
1.3
V1 ColdFire Core
The MCF51CN128 series devices contain a version of the V1 ColdFire platform that is optimized for area
and low power. The CPU implements ColdFire instruction set architecture revision C (ISA_C) with a
reduced programming model:
•
No hardware support for MAC/EMAC and DIV instructions
•
Upward compatibility with other ColdFire cores (V2–V5)
An integrated multi-master crossbar switch on the ColdFire system busses provides access to system
resources by the CPU and Ethernet controller. The CPU configuration register has one bit for control of
the crossbar switch.
For more details on the V1 ColdFire core, see
1.3.1
User Programming Model
illustrates the integer portion of the user programming model. It consists of the following
registers:
•
16 general-purpose 32-bit registers (D0–D7, A0–A7)
•
32-bit program counter (PC)
•
8-bit condition code register (CCR)
1.3.2
Supervisor Programming Model
System programmers use the supervisor programming model to implement operating system functions.
All accesses that affect the control features of ColdFire processors must be made in supervisor mode and
can be accessed only by privileged instructions. The supervisor programming model consists of the
registers available in user mode and the registers listed in
.
Figure 1-2. Supervisor Programming Model
31
19
15
0
CCR SR
Status register
OTHER_A7 Supervisor A7 stack pointer
Must be zeros VBR
Vector base register
CPUCR
CPU Configuration Register